Method and apparatus for preparation and use of ozone water

ABSTRACT

A system for production of water having dissolved ozone includes a water feeding section, a container part, an ozone feeding part for feeding ozone to a mixing part dissolving ozone in the water, the mixing part drawing water from the lower part of the container, an ozone measuring part for measuring the ozone concentration of the water in the container, a water pump for circulating the water from the lower part to an upper part of the container in dependence of the measured ozone concentration and from the ozone feeding section to the mixing part in dependence of a predetermined ozone concentration, the container having an outlet for water having the predetermined concentration of ozone.

As the population in the world grows and as the movements of peopleincreases the amount of viruses and micro-organisms also increases. Weall come into contact with at least some of these during our dailylives. These contacts result in illness and even causes death.

For long time the use of chlorine and derivatives thereof, asdisinfectant, has prevailed. During later years drawbacks have beennoted in connection with the use of chlorine and related compounds.

Ozone has been used for disinfectant purposes. It has a strong oxidizingeffect on materials coming into contact with the ozone and is veryeffective as a bactericide even when used against the most resistantbacteria and virus species e.g. listeria, MARS and escherichia coli etc.Thus chlorine and other dangerous and poisonous disinfectants may bereplaced.

In EP,A2,0712634 is disclosed a system for treating and sterilization ofbiological, solid, etc hospital residues, in which residues are grindedand treated with a mixture of oxygen+ozone+carbondioxide+water//oxygen+ozone+water. The system is designed to dissolvethe gaseous components in the water and the mixing system moves thewater into an absorption and de-gasification tank whereafter the waterplus the gases are put into the washer which contains the material to besterilized. The crushed residuals are then subjected to a continuos bathwith permanent recirculation with the water mix. The gases are mixedwith the water in increasing amounts in the separate parts of thesystem.

In RU,C1,2068263, is described how to treat wounds with ozone in orderto speed up the healing process.

A device for increasing the intensity in the spraying of ozone isdescribed in DE 3215371.

A device for medical treatment using ozone is described inEP,A1,0,450,103, in which during the treatment the part of the bodywhich is to be treated with ozone gas is trust into a sealed containerwhere the ozone is allowed to pass through the sealed portion.

Devices for making steam having an admixture of ozone are know e.g. fromFR,A,2484279.

Herein below the following words are used:

Ozone-water—A water-ozone solution (also termed Active water), which isa sterile water rich in ozone. The Ozone -water may optionally containoxygen.

A specific problem as regards the use of ozone is the relativeinstability of the same compared to oxygen. Ozone spontaneously decaysto oxygen with a half life of 3 days at 20° C., 8 days at −15° C., whichshow the temperature dependence of the decay. These figures refers tothe gas. These data are cited from Römpp, Chemie Lexicon, Thieme, Band7, 1991.

Ozone is a highly reactive and as such harmful to materials and livingmatter. Therefore locations in which ozone is manufactured or is evolvedas a by-product of some machinery or chemical reaction must be wellventilated on account of the harnfuil effects caused by the gas.

The aim of the invention is to be able to use ozone in a safe andpredictable way in different applications.

It is also an aim of the present invention to generate ozone-water in asafe and reproducible way, giving a controlled gas and water flow.

It is also an aim of the invention to generate this ozone-water inpredetermined concentrations, also insuring a controlled temperature andpressure of the solution.

A further aim is to accomplish an optimal solubility of the ozone gas inthe water

A further aim of the invention is a system for accomplishing the aboveaims

Yet another purpose is a device for administering the ozone-water in theform of a spray or in liquid form.

Yet another purpose is to produce ozone and ozone-water of the purestquality.

Yet a further object is to combine the system with various means fortreatment.

These and other objects, advantages and features of the presentinvention will be more readily understood from the following detaileddescription of the preferred embodiments thereof, when considered inconjunction with the drawings, in which like reference numerals indicateidentical structures through the several views, and wherein:

FIG. 1 shows an over-all view of one embodiment o the system accordingto the invention

FIG. 2 shows a schematic overview of the conduits, valves, tank, etc. ofone embodiment of the invention according to the invention.

FIG. 3 shows a schematic overview of the control system of oneembodiment of the mixing chamber according to the invention.

FIGS. 4a and b shows on embodiment of a mixing chamber according to theinvention.

FIGS. 5a, b, c shows a second, a third and a fourth embodiment of amixing chamber according to the invention.

FIG. 6 shows a flow-cell used in experiments for assessing the effect ofthe method according to the invention.

FIGS. 7a and 7 b show the results of experiments made using equipmentand method according to the invention.

FIG. 8 shows the results of another experiments made using ozone-watersolution and method according to the invention.

FIGS. 9 and 10 shows two embodiments of a purification and/or analysepart system to be used in conjunction of to be integrated with thesystem according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1 is shown the general principle represented by one embodimentof a system according to the invention. The system of this embodimentcomprises an inlet 10 for oxygen/air, an inlet 11 for water, a unit 20for generation of ozone, a unit 30 for treatment of incoming water, amixing unit 40, a PLC control system 50, controllable valves andconduits, and leads connecting the valves and the control system 50. Theincoming water is filtered, de-mineralised, and separated into two ormore water fractions in the unit 30 for treatment of incoming water andthereafter used in the mixing unit 40. The incoming air/oxygen istreated in the ozone generator unit 20 and thereafter sent to the mixingunit 40 to be mixed with the treated water. After the mixing unit theozone-water may be saved temporarily in a dissolution tank, below tank(not shown), or used directly or the ozone may also be used directly.

A further description of the conduits and valves is given below inconnection with a more detailed description of the system as such, inFIG. 2 and the control system in FIG. 3.

Referring now to FIG. 2, in which an embodiment of the system forproducing ozone-water, ozone (active water) according to the inventionis shown. The system comprises an inlet conduit 71 for water in whichconduit a controlled reducing valve V1, e.g. a magnetic valve, isarranged, following that a unit 30 for treatment of incoming water,filtering and de-ionising (de-mineralising) and separation into twofractions exhibiting two different pH-values, an inlet conduit 70 forair or oxygen gas to the ozone generator 20, which may be a commercialozone generator of a type which produces the necessary ozone, e.g.Plasma Resonance Electron, Ozonice, Japan.

The electrolysis chamber in the unit 30 should be rinsed at intervalsand is drained via a separate drain conduit 81 to an outlet 13. Atemperature regulating function may be built in at/or near the unit 30.

In the conduit 70 a controlled valve V2, a pressure sensor PR and a flowsensor F1 are arranged.

The unit for filtering and de-mineralising is electically controlled andmechanically adjusted. The pH-value of the water is adjusted by dividingthe water into at least two fractions using e.g. an apparatus asdescribed above. Such apparatus are commercially available e.g. analkaline ionizer, Bion Q Water Ionizer from DAE-A Medical Ltd.

The adjustment of the water may be performed in one step or in severalsteps depending on the quality of the war that is used as input in thesystem. The water flows via conduit 83, through a check valve BV1 to atank 60. The treated water is fed to the tank 60 in which there is ageda liquid level indicator 90. There may of course be arranged more thanone liquid level sensor e.g. one for the maximum level and one for theminimum level.

From the unit 30 for treatment of the incoming water there are two moreoutlets. One outlet 13 is a drain for surplus water or the like which isdrained through a conduit 81, and also a conduit 82 and an outlet 15through which more or less alkaline water is available for washingpurposes etc. This outlet is of course optional and not be present inall embodiments of the invention, since if the alkaline water is notneeded it may be drained through the conduit 81.

A polarographic sensor S1 for sensing of the of the ozone concentrationis preferably arranged at the outlet from the tank, or in an outletconduit 84 from the tank 60. It could also be arranged in the tank 60.

The ozone sensor may of course be of any kind which would suffice forthe intended use. In this specific embodiment a ozone sensor availablefrom Toa Electronics, Tokyo, Japan.

At or near the upper part of the tank an outlet conduit 72 is arrangedhaving a check valve BV2 for hindering a vacuum from forming when thetank is emptied. The check valve could of course also be magneticallycontrolled. A branch conduit 73 is arranged in the conduit 72 betweenthe tank 60 and the check valve BV2. In the conduit 73 a spring loadedvalve BV3 is arranged, which ensures that a constant pressure is upheldin the tank 60 until some or all of the content of the tank 60 isemptied.

After the ozone-generator a controlled three-way valve V3 either leadsthe produced ozone to a mixing chamber BK via a conduit 75, in which acheck valve BV4 is situated in order to stop the flow running backwardsin the conduit 75, or leads the produced ozone out from the system viaconduit 76.

When the level indicator indicates that the predetermined level of thewater in the tank 60 has been reached the valve V1 is closed. The valveV2 opens the supply of oxygen to the ozone generator. The oxygen flowpasses the pressure sensor PR and the flow sensor F1. The ozonegenerator according to the embodiment comprises a voltage/frequencyconverter, which is coupled to an electrode, which is placed in an aircooled chamber. When the oxygen passes the electrode ozone is produced.Important parameters for optimal production of ozone is flow velocity ofthe oxygen over the electrode and the effect of the generator.

There are preferably two circulatory paths for the ozone-mixed water inthe system. The first one comprises a branch conduit 77 which isarranged at the lower part of the tank 60 leading the ozone watersolution to a pump P1 and back into the tank 60. The pump continuouslycirculates the water from the tank 60 to the mixing chamber BK and backto the tank.

Near the bottom of the tank 60 a conduit 84 is arranged which leads to acontrolled valve V4.

The controlled valve V4 may either let the ozone-water solution leavethe system through an ozone-water outlet 12 or recirculate the solutionpreferably to the upper part of the tank 60 through a conduit 78.

The produced ozone gas flows via the valve V3 and the conduit 75 and acheck valve BV4 to the mixing chamber BK, where the produced ozone gasis mixed with the water pumped by the pump P1 from the tank 60 viaconduit 77. The chamber comprises according to the invention acombination of a diffuser, which creates a turbulent water flow andporous member through which the gas comes into contact with the water,this member is e.g. a sintered atomising gas nozzle, (below callednozzle or gas nozzle), preferably made from acid-proof material having apore size of 0.2-10 microns. The mixing sequence continues until thepredetermined ozone concentration in the tank 60 has been attained Themixing chamber is described further in concentration with FIG. 4.

The ozone concentration is preferably measured by polarography by thesensor S1 at predetermined intervals. In other embodiments other typesof sensors may be used as would be obvious to the man skilled the art.

As soon as the concentration falls below a predetermined minimum valuethe sequence for preparing the ozone water is repeated. By pumping theozone-water solution from the tank through the conduit 77 via the pumpP1 and the mixing chamber BK and thereafter back to the tank it isensured that the concentration of the ozone-water be kept at thepredetermined value at all times.

The conduit 77 when returning the water to the tank preferably entersozone-enriched water coming from the mixing chamber BK below the levelif the liquid in the tank.

When ozone-water is not withdrawn from the tank for some time the ozoneconcentration is very slowly declining. The pump P2 is used to create acirculatory movement of the ozone-water past the ozone concentrationmeasuring sensor and through the tank by pumping the ozone-water fromthe bottom of the tank via the valve V4 back to the tank 60 returningthe ozone-water to the upper part of the tank.

Surplus of ozone is allowed to pass out through the check valve BV3 to aconverter 25. In the converter the ozone is converted catalytically tooxygen and thereafter allowed to exit from the system via an outlet 26from the converter 25 and any liquid formed during the process may bedrained through the conduit 27.

Drawing off the ready-made solution, the active water, from the tank isaccomplished in this embodiment by opening the magnetic valve V4 andletting the pump P2 empty the tank 60. In doing so the valve BV2prevents a vacuum from forming in the tank.

From the system there is also a possibility to discharge ozone in theform of gas through the three-valve V3 depending on if ozone in the formof gas is needed for the specific application at hand.

A control system (PLC) is arranged in order to control e.g. the valvesand parameters, such as temperature, and the level in the tank thegeneration of ozone, the filtering of the water and the mixing of ozoneand water and the release of ozone of ozone-water (active water) fromthe system.

An example of an arrangement of a control system to be used in themethod and the device according to the above described embodiment isshown in FIG. 3.

To be noted is that the embodiment according to FIG. 3 comprises anextra pump P3 compared to the embodiment in FIG. 2 for withdrawal ofactive water via a branch conduit 79 before the pump P2. In the branchconduit 79 a controllable valve V5 is arranged before pump a P3. Aconduit 80 connects the outlet from the pump P3 with the ozone-wateroutlet 12. This extra pump and conduit is added to allow for a fasterflow from the tank 60.

The control system comprises a control unit 50, one or more controlprograms (ex. of control program sequences below), A/D-converters,processing means, input and outputs means for analogue and/or digitalsignals and/or control signals. In this embodiment there are 14 leadsfor controlling valves in dependence of the control program and ofmeasured parameters, such as temperature, flow, concentration, etc.

The control unit 50 may be controlled manually from a control panel (notshown). Using the panel different sequences may be chosen depending onthe type of application the system is used in. The parameters of thechosen control sequence program preferably relate to empirical values.

The unit 30 for treatment of incoming water (filtering anddemineralizing) uses the following signals: on/off, stepwisepH-adjustment, flushing of the electrolysis chamber (not shown) of theunit 30, and possibly control and adjustment of the water temperature.

The ozone generator 20 uses the following signals: off/on, stepwisepower control (the electrode potential).

The ozone sensor 51 and the circuitry thereof generates an analogueA/D-signal which is used in the chosen control sequence.

The control unit 50 controls valves and pumps and receives signalsdepending on sensed or measured parameters all in dependence of thechosen sequence. Signals on lead 101 controls the incoming water bymeans of the valve V1. Signals on lead 102 measures the pressure theincoming air/oxygen by means of the pressure gauge PR. Signals on lead103 controls the valve V2. Signals on lead 104 controls/measures theincoming air/oxygen flow by means of the flow meter F1. Signals on lead105 controls the ozone generator unit 20. Signals on lead 106 controlsthe incoming air/oxygen by means of the three-way valve V3. Signals onlead 107 controls the filtering and demineralizing in the unit 30 fortreatment of water. Signals on lead 108 controls the active water in therecirculation measuring circuit by means of the valve V4 and the releaseof the ozone-water solution (active water) from the system. Signals onlead 109 from the ozone sensor 51 are used for controlling the process.

Signals on lead 110 controls the pump P2, on lead 111 controls the pumpP1, on lead 112 controls the valve V5, on lead 113 controls pump P3 andon lead 114 signals from the liquid level indicator 90 is passed to thecontrol unit.

In FIGS. 4a and 4 b is shown an embodiment of a mixing chamber accordingto the invention. The numbers used for details in FIGS. 4a and 4 bcorrespond to each other. In FIG. 4a the chamber is shown from theoutside displaying an inlet 1 for water and one inlet 2 for ozone and anoutlet 3 for the water/gas solution. The inlet 1 for water and theoutlet 3 are connected by means of an inner conduit 9 in the form of abore or the like. In FIG. 4b the same chamber is shown in another viewand partly in section. From the ozone inlet 2 the ozone enters a centralbore 6 in the nozzle 5, which bore 6 has a dead-end. The ozone will thushave to migrate through the nozzle 5 and enter the flow of water outsidethe nozzle. Thus the gas is dispersed in the form of very fine bubblesin the water in the chamber using the atomisation nozzle according tothe invention. The nozzle is preferably made from sintered ceramics orstainless steel.

An important factor in choosing the material in the mixing chamber isthat a material is chosen, which, if possible, is inert to ozone andwhich does not show any catalytic effect on the decay of the ozone. Inorder to achieve a good mixing of the ozone gas with the water it isessential that the gas is atomized by means of the sintered atomisingnozzle or any other injection means giving the same effect.

In FIGS. 5a, 5 b, and 5 c three further embodiments of the mixingchamber according to the invention are shown schematically. The numbersused for details common to FIGS. 5a, 5 b, and 5 c correspond to eachother. In the figures the following is shown denoted by correspondingnumbers: inlet 1 for water, inlet 2 for ozone, and outlet 3 for thewater/gas solution.

In FIG. 5a a nozzle 5 is arranged in an inner conduit 9 between a waterinlet 1 and an ozone-water outlet 3. The nozzle exhibits a centralthrough-bore 7 through which the water passes from the inlet to theoutlet. The nozzle is arranged such that all the water has to passthrough the bore 7. The ozone inlet 2 comprises a conduit which ends ina chamber 8 sealed off from the water conduit by the nozzle as suchmaking sealing contact with the conduit walls. The chamber 8 is filledwith ozone which migrates through the nozzle into the water passing fromthe inlet 1 to the outlet 3 through the central through-bore 7. Thethrough-bore preferably exhibits a smaller cross-section area halfwaythrough the bore than at the two ends thereof.

In FIG. 5b a nozzle 5 is arranged in an inner conduit 9 between a waterinlet 1 and an ozone-water outlet 3. The nozzle exhibits a central blindbore 6 through which ozone gas enters from the ozone inlet 2. The nozzleis arranged across the conduit 9. The water will thus have to pass bythe nozzle 5 where the ozone will mix with the water. The conduit 9 isdesigned such as to give as much free area of the nozzle contact withthe passing water, while still providing a constriction in the conduit.This is clearly seen from the cross-section B—B in FIG. 5b.

In FIG. 5c a nozzle 5 is arranged in an inner conduit 9 between a waterinlet 1 and an ozone-water outlet 3. The conduit 9 is arranged to make a90° turn where the ozone inlet emerges into the conduit 9. The nozzleexhibits a central blind bore 6 through which ozone enters from theozone inlet 2. The nozzle is arranged in the conduit 9 such that thewater from the inlet will pass on the outside of the nozzle 5 along mostof the nozzle outside area as to give as much contact with the passingwater, while still providing a constriction in the conduit.

Examples of control program sequences is given below to illustrate thefunctioning of the system.

A control program sequence for cleaning/sterilising of a medicalinstrument may be performed accordingly:

A chamber (not shown) adapted to the medical instrument is connected tothe system. The outlet from the chamber is connected via the convertersystem to a drain. The converter system may of course be a separate oneif so is desired.

Two embodiments of subsystem for sterilisation is describe inconjunction with FIG. 9 and FIG. 10 in which measurements are made inorder to ensure that set goals are attained.

When the on-button is pressed on the instrument panel the valve V1receives a signal opening the water supply to the system. At the sametime the water treatment unit 30 is given a signal to regulate thepH-value of the water. Water having different pH-values may be separatedin the unit. Water having a low pH-value is directed to the tank 60 andthe water having a high pH-value, alkaline water, is directed to thechamber for a first cleaning of the instrument.

When the liquid level indicator 90 signals that the predetermined liquidlevel in the tank 60 has been attained a signal is given to V1, whichcloses.—The pressure gauge indicates that (air/)oxygen is present—asignal opens V2 and the ozone generation on the ozone generating unit 20is initiated by a signal from the control unit 50 (control system100)—pump 1 is started by a signal—pump P2 is started by a signal. Themixing of ozone and water is continued until e.g. 5 ppm has beenattained in the solution—a closing signal is sent to V2, and signals aresent to P1 and the ozone generator to stop—signals are sent by thecontrol sequence program to open the valve V5 and start pump P3 (highflow) and the active water is pumped into the chamber for e.g. 10sec.-V5 is closed and P3 is stopped—a signal opens V4 (low flow) to thechamber for e.g. 4 min. Thereafter the controlled valves V2 and V3 areopened by the control program sequence and the ozone generator unit 20is given a signal to start producing ozone, and ozone gas is allow toflow through the chamber during e.g. one minute. This sequence may berepeated trice.

It is within the field of the invention to provide control leads andcontrol functions within the control program sequence for controllingvalves, pumps, brushes etc. of the chamber.

A control program sequence for filling of spray bottles, which spray maybe used for i.a. disinfectant uses may be performed accordingly:

A spray bottle holder (not shown), for one or several bottles isconnected to the outlet from the system. On the on-signal the valve V1is given a signal opening the valve and thereby providing water to thesystem. At the same time the water treatment unit 30 is given a signalto regulate the pH of the water. Water having a low pH fills the tank60, and the alkaline water is drained from the system. As the liquidlevel indicator 90 sends a signal to the control unit the valve V1 isclosed—it is controlled that the pressure gauge PR indicates presence ofair/oxygen—the valve V2 is given a signal to open and the ozonegenerator unit 20 is given a signal to start generating ozone—the pumpP1 is given a start signal—the pump P2 is given a start signal. Theadmixture of ozone into the water is started, and is stopped when theconcentration measured in the water from the tank reaches 2 ppm—thevalve V2 is closed and the ozone generating unit 20 and the pump P1 arestopped—if and when the ozone concentration declines below 1.5 ppm, theozone admixture sequence is repeated.

The concentration of the ozone-water solution is controlled by thepredetermined value, represented by programmable variables in thesequence.

When the spray bottle is to be used it is place in the spray bottleholder—the bottle is emptied from any water therein.—The valves V2 andV3 are given signals to open, the ozone generator unit 20 is given asignal to start generating ozone and the bottle is flushed with ozone,it could of course also be flushed with the ozone-water solution. A pushbutton for filling acts on the valve V5 and the pump P3, which fills thebottle—the filling of the bottle may for instance be time control, otherpossibilities are within the reach of the man skilled in the art. Whenthe bottle has been filled a safety check may be made on the water inthe bottle or in connection with the filling of the bottle e.g. inconnection with the outlet from the system. If the ozone connection istoo low an alarm will preferably be activated indicating that theconcentration of ozone in the bottle is too low.

A procedure for the water treatment in the unit 30 and in connectionwith this may be performed accordingly.

Tap water, possibly from the municipal water supply, is purified usinge.g. an active carbon filter. Particles of rust, chemicals organicmartial, paint etc. is absorbed in the filter. The service life of thefilter may be controlled by the setting of a time limit.

The water purified in the filter is thereafter passed through anelectrolysis cell (not shown), which is constructed fromplatinum/titanium and SUS-316 acid-proof steel. By choosing theappropriate material an optimal electrolysis of the water is attained.The electrolysis cell is preferably cleaned each 10 minutes during app.30 sec.

By electrolysis of the water ions are separated such that some areguided to the positive electrode and some to the negative electrode. Thepositive ions directed to the negative electrode gives alkaline waterand the negative ions directed to the positive electrode give acidwater. In the exemplary system discussed above the water from thepositive electrode (acid water). This fraction of the water is used tomake ozone-water solutions having different degrees of concentration.There is also a possibility for use of the alkaline water coming fromthe negative electrode for specific applications.

The requirements as to the water used are that the temperaturepreferably should be within the interval 5° C.-10° C., the conductivityof the treated water should preferably be <80 μS/cm, the water shoulddisplay the quality called soft water, and the preferred pH-interval is2-4 pH units.

By using tap water from a municipal source or the like higherconcentrations of Cl⁻, S⁻, and P⁻ are attained. This results in a lowerpH and better conditions for dissolving ozone in the water. Theozone-water solution according to the invention will be more stable in asolution having a low pH.

An application in which the apparatus/system according to the inventionmay be used is a method for measuring the amount of organic contaminantsin a liquid. This application requires that the ozone concentration inthe ozone gas is closely regulated.

The invention also resides in feeding ozone gas of a determinedconcentration to a, preferably closed, container in which the liquidhaving organic contaminants therein is kept. The feeding of ozone gas tothe container results in reaction between the contaminants and theozone. As long as there are contaminants in the container the ozone willbe spent by reaction. This implies that as long as there arecontaminants in the receiver no ozone will be possible to detect in thecontainer. Respect must also be paid to the natural decay of the ozone.

Other parameters having influence on the measurements of the above typeis contact time, temperature, ozone gas concentration, the material inthe container as such and the type of contamination and theconcentration of the same. These and other parameters to be evaluated inthe separate instance are to be taken into account in the measurementsas to reaction speed and the expected end result.

Experiments were undertaken in order to make certain the influence ofcertain variables on the results and to validate the effect of theozone-water.

In FIG. 6 a flow-cell is shown which was used in the experimentsdescribed below. The results are shown in FIGS. 7a and b.

The aim of the experiments were to show the sterilizing effect of theozone-water-solution according to the invention. Two concentrations wereused, 3 and 6 mg/l, resp. The organisms studied as examples of such wereBacillus Cereus and Staphylococcus aureus on glass surfaces.

Bacillus Cereus is patogenous and also a common cause to the destructionof food products. In their spore form they are resistant towards dryingout, high temperatures, and chemicals.

Staphylococcus aureus is a Gram-positive coccus which does not have aspore form but still is very resistant towards drying out and differentchemicals. It forms toxins and can cause food poisoning.

Materials and Methods:

The methods used in these experiment is in accordance with the methodsand experiences the SIK (Institutet för Livsmedel och Bioteknik,Gothenburg, Sweden). Respects has also been taken to the methods forvalidation of disinfectants, which are being established by thetechnical committees within the EU. Here is referred to the work done byTC216. The Bacteria were fastened and dried on hydrofobic glasssurfaces. They were exposed to ozone-water during determined timeperiods and thereafter the number of surviving bacteria was analyzed.

Micro-organisms:

Spores from two different strains of B. Cereus were used. The so calledstrain (ATC 14579, SIK 229) and a strain isolated from butter from adairy (SMR 781, SIK 341). Vegetative cells of Staphylococcus aureus(ATCC 6538, SIK 295) were also used.

The glass surfaces and the preparation of these:

The glass surfaces used were microscope slides, which by treatment withmethyl silane where rendered hydrophobic.

Bacillus spores and the Staphylococcus were suspended in a physiologicsalt solution in a concentration of 10⁷ to 10⁸ macro-organisms/ml. Theslides were suspended in this solution for an hour. Meanwhile themacro-organisms fastened onto the surfaces. The slide were rinsed withdistilled water and dried in room temperature for about 12 hours.

In order to provide the ozone-water a system was used comprising anozone-generator of the type Ozonize. This unit uses a plasma resonanceelectrode. Oxygen was used to generate ozone, which cuts the developmentof NO_(x)-gases considerably.

In order to have pure water of uniform quality de-ionized water,Kenmityl T-vatten, was used.

The ozone-water solution was prepared according to the invention using adevice, which is shown in FIG. 4 by a technique we have named“Diffu-Z-ektor-technic”. This technique is a combination of diffusionand injector technique. This technique gives a controlled gas and waterflow.

The slides 101 were mounted in a flow cell 102 shown in FIG. 6,. Theozone-water was passed through the flow cell, from the inlet 103 to theoutlet 104. The flow in the cell was at this occasion 0,1 l/min. Tocontinuously control/monitor the concentration of the concentration ofthe dissolved ozone of the water passing in and out of the flow cell apornographic membrane electrode TOA was used. The measurement instrumentwas connected both to the inlet and the outlet from the flow cell. Twoconcentrations of ozone in the water was used, 3 mg/l and 6 mg/l.

The validation of surviving micro-organisms:

The reference values—i.e. the number of bacteria per slide beforeexposition to the ozone-water was enumerated using swab-technique. Thesurfaces were swabbed using an alginate swab and smear was made onTGE-plates (Trypton Glykos Extract Agar).

The values after exposition were measured by form-molding nutrient agar(Trypton Soya Agar) having an admixed color indicator (TetrazoliumChloride) over the bacteria on the slide in near connection to theexposition for the ozone-water.

Results and Discussion:

The results are represented in Table I and shown in FIGS. 7a and 7 b.From these diagrams, 7 a representing the test run using a concentrationof 3 ppm ozone and 7 b a the test run using a concentration of 6 ppmozone, there can be seen no logical differences between the specimenstreated during 5, 10, and 15 minutes. This may be understood such thatthere is an almost instantaneous or at least a very fast action of theozone-water and that after 5 minutes only remains a so called tail, i.e.after 5 minutes the survival speed remains constant.

One difference may be noted in that the higher concentration of ozonegives a better effect. The noted logarithmic reductions for the twostrains of Bacillus and for the Staphylococcus was app. 2 logarithmicunits for 3 ppm and 3 logarithmic units for 6 ppm. the Bacillus strainwas the most resistant.

TABLE 1 CFU = colony forming unit 229 341 295 B. cereus typestrain B.cereus dairystrain S. aureus Measured Average ± Measured Average ±Measured Average ± Treatment CFU value SD CFU value SD CFU value SDInitial value 2.6 × 10³  1.8 × 10⁵ ± 1.4 × 10⁵  6.0 × 10⁵ ± 17.0 × 10³ 8.4 × 10³ ± 3.4 × 10⁵ 1.2 × 10⁵ 1.1 × 10⁶ 3.8 × 10⁵  2.0 × 10³ 8.0 ×10³ 0.7 × 10⁵ 1.0 × 10⁶  5.0 × 10³ 0.04 × 10⁵  8.5 × 10⁵ 17.0 × 10³ 1.8× 10⁵ 4.0 × 10⁵  1.0 × 10³ 2.0 × 10⁵ 3.0 × 10⁵ 3.9 × 10⁵ 3 ppm 5 min 043 ± 51 200 408 ± 520 2   2 ± 1.6 30 25 3 100 1000 0 3 ppm 10 min 100100 ± 0  500 533 ± 451 10 503 ± 495 100 100 1000 100 1000 500 3 ppm 15min 25 50 ± 25 1000 1000 ± 0   2 18 ± 28 50 1000 50 75 1000 1 6 ppm 5min 0 0 ± 0 25 25 ± 0  3 13 ± 15 0 25 5 0 25 30 6 ppm 10 min 15   7 ±7.2 25 142 ± 142 8 9 ± 1 5 300 9 1 100 10 6 ppm 15 min 0 0 ± 0 500 192 ±267 2 2 ± 1 0 50 1 0 25 3 6 ppm 1 min 28 — 100 — — — Gas 30 min 1 — 10 —0 —

In a second test run shown in FIG. 8 the effect of the zone solutionaccording to the invention is shown on two different bacteria: Feacalstreptococcus and Pseudomonas aeruginosa. The analysis was performed byVattenvardslaboratoriet VVL, Stockholm, Sweden.

The bacteria were inactivated by a 1 ppm ozone water solution and theresults in table 2 were obtained.

TABLE 2 Bacteria cfu before treatment cfu after treatment Feacalstreptococcus 88 0 Pseudomonas aeruginosa. 66 0 cfu = concentration ofbacterias/ml

This clearly shows the effect of the ozone water according to theinvention.

The examples in the description has been given in order to demonstrateand clarify the system and the method for production of the ozone waterand the ozone water according to according to the invention and shouldnot be considered limiting the scope of the invention.

The water prepared according to the method according to the presentinvention is useful in several aspects. It may be used in a method fordetection of bacteria or other living matter, specially contaminatingmaterial. The method comprises supplying water, having dissolved ozonetherein of a known concentration to an object, measuring the ozoneconcentration in said water as said water is removed from the object,and thereafter measuring the difference in concentration between thewater supplied and the used water. As the ozone is consumed by thecontaminating material present the difference in concentration may beused as a measure of the amount of bacteria or other living matterpresent on or in said object. This may be accomplished e.g. by means ofa container having an inlet for said water containing ozone of apredetermined concentration and an outlet for said water. At the outletfrom the container an ozone concentration measurement means is arranged.Control means are preferably arranged to control the measurement methodautomatically.

A further use of the water prepared according to the invention is theuse of said water containing ozone having a predetermined concentrationof ozone for destruction of cells, e.g. cancer cells. This may beaccomplished on account of the sensitivity of abnormal cells e.g.cancers cells being more sensitive to ozone than normal cells. In orderto accomplish this, a device may be used which comprises means forselectively distributing the water comprising ozone dissolved therein,means for controlling the amount of said water distributed and alsomeans for removal of not-spent water so as to avoid excessive contactbetween the water and normal cells. The device preferably also has anautomatic control system.

In FIG. 9 is shown a detector and purification subsystem according tothe invention to be used with or integrated in the system according tothe invention. From the system for production of ozone-water or ozonedescribed above ozone-water or ozone gas entering an inlet 901 isallowed to pass through conduit 902. The gas thereafter passes by asensor 910 for measuring ozone concentration and/or ozone amount passinginto the subsystem. The sensor 910 may be left out and the values fromthe sensor (51) of the main system may be used instead. The ozone-wateror ozone gas thereafter follows a conduit 903 and enters a treatmentchamber 912, which may be a chamber containing utensils to be sterilisedor in itself comprise an apparatus, such as a dialysis apparatus or thelike. The subsystem must in the latter case be provided with connectionsfor sealingly attaching the apparatus. The used ozone-water or ozone gasexits the chamber via a sensor 911 and from there to destruction of theozone or the like via a conduit 905. A processor/measurement unit 913controls the two sensors and their respective values via conductors 920and 921.

If the sensor 910 indicates a higher measurement value than the sensor911 this shows that the ozone is consumed by some organic matter such asbacteria. When there is balance between the two measurements indicationis given that the utensils in the chamber 912 or the unit 912 isdisinfected.

In FIG. 10 another embodiment of the above subsystem is shown. In thissubsystem only one sensor is used.

From the system for production of ozone-water or ozone described aboveozone-water or ozone gas enters an inlet 1001 and passes through aconduit 1002 and passes by a three-way valve. The ozone-water or ozonegas thereafter either follows a conduit 1003 and enters a treatmentchamber 1012, which may be a chamber containing utensils to besterilised or in itself comprise an apparatus, such as a dialysisapparatus or the like. The used ozone-water or ozone gas exits thechamber via a conduit 1004 having a three-way valve and passes a sensor1011 for measuring ozone concentration and/or ozone amount passing outfrom the subsystem and from there to destruction of the ozone or thelike via a conduit 1005.

In order to measure contamination, control disinfecting result etc. theozone gas or the ozone-water is in turns led via conduit 107 therebybypassing the unit/chamber 1012.

A processor/measurement unit 1013 controls the sensor 1011 and the two2-way valves via conductors 1021, 1022, and 1023 in the same manner asin FIG. 9.

What is claimed is:
 1. A system for production of water having ozonedissolved therein, said system comprising: a water feeding means(11,V1,71,30,83), a container means (60), an ozone feeding means(10,70,V2,F1,20) for feeding ozone to a mixing means (BK) for dissolvingozone in said water, said mixing means (BK) drawing water from a loweroutput of the container (60), ozone measuring means (51) for measuringthe ozone concentration of said water in the container (60), waterpumping means (P1, P2) for circulating said water from the lower part ofthe container (60) to the upper part of the container (60) in dependenceof a measured ozone concentration in said water and said ozone feedingmeans feeding ozone to said mixing means (BK) in dependence of apredetermined ozone concentration value, said container (60) having anoutlet (84,P2,84,V4,12) for water having the predetermined concentrationof ozone, said system adapted to maintain a predetermined liquid levelin said container, said system further comprising a control unit (50)for controlling the system in dependence of measured physical parametersin the system.
 2. A system according to claim 1, characterized in that aconduit (77) is adapted to return the water having ozone dissolvedtherein from said mixing means (BK), to a point in the container (60)below the liquid level in said container (60).
 3. A system according toclaim 1 or 2, wherein said water feeding means (11,V1,71,30,83)comprises: means (V1) for controlling the flow of water to the systemand a filtering and de-mineralizing unit (30).
 4. A system according toclaim 3, wherein said ozone feeding means (10,70,V2,F1,20) comprises:means (V2) for controlling the flow of oxygen gas and/or air to thesystem, an ozone generator, and means (V3) for distributing the flow ofozone gas to the mixing means (BK), or to an outlet for ozone gas (14),a pressure sensor (PR), and a flow sensor (F1).
 5. A system according toclaim 4, wherein said mixing means (BK) comprises: a chamber having awater inlet (1) for water from the lower part of said container (60), anozone inlet (2) for ozone from said ozone feeding means, said ozoneinlet (2) having a diffusor means comprising a porous member, preferablyexhibiting a pore size of approx, 0.2-10 microns, a water outlet (3) forwater having dissolved ozone through an outlet conduit leading to theupper pan of the container (60), wherein there are control means formonitoring the addition of ozone in dependence of the measured ozoneconcentration.
 6. A system according to claim 5, characterized in thatthe ozone concentration measuring means (51) is arranged in the outletconduit (71) from the lower part of the container (60), pumping means(P2) provided to withdraw said water from the bottom of the container(60) past the concentration measuring means (51) and in dependence of acontrol signal from the control unit (50) either return the water to apoint below said predetermined liquid level in the container (60) or todeliver said water through the outlet (84,P2,84,V4,12) for water havingthe predetermined concentration of ozone.
 7. A mixing device forestablishing a liquid-gas mixture, comprising: a liquid inlet (1), a gasinlet (2) and a liquid-gas mixture outlet (3), and a conduit (9) forjoining said liquid inlet (1) and said liquid-gas mixture outlet (3),characterized by a porous member (5), at least at the upstream end ofthe porous member (5) being in scaling contact with the inner walls ofsaid conduit (9), said porous member (5) having a first surface being incontact with the liquid and second surface being in contact with thegas, the dimensions of said conduit (9) being such that a pressuredifference is created in the liquid before and after said member (5)such that the gas is made to diffuse through said porous member (5),characterized in said porous member (5) exhibiting a through-bore (7)essentially co-axial with said conduit (9), the bore (7) constituting aconstriction of the conduit (9), the inside walls of said through-bore(7) constituting said first surface, said inner wall having anessentially circumferential recess formed in the inner walls of theconduit essentially along the porous member (5) said recess connectedwith the gas inlet (2) giving the gas access to the outside of theporous member, said outside constituting said second surface.
 8. Amixing means according to claim 7, characterized in said porous member(5) exhibiting a blind-bore (7), the blind-bore (7) communicating withthe gas inlet (2), the inside walls of the blind-bore (7) thusconstituting said second surface, the outer surface of the porous member(5) constituting said first surface in contact with the liquid, saidporous member (5) constituting a constriction of the conduit (9).
 9. Amethod for production of active water, water having dissolved ozonetherein, characterized by the following steps: feeding filtered andde-mineralized water to a container to a predetermined level;re-circulating the water from the bottom of said container through aconduit comprising pumping means and mixing means; dissolving ozone gasin said re-circulated water in said mixing means under controlled inletflows; feeding said water having dissolved ozone to said container,measuring the instant ozone concentration of said water having dissolvedozone; said water having dissolved ozone re-circulated through themixing means under addition of further ozone in dependence of saidmeasurement of the ozone concentration; said last step repeated when themeasured ozone concentration is below a predetermined value.
 10. Amethod according to claim 9, characterized by said method alsocomprising the step of re-circulating the water having dissolved ozonethrough a separate conduit in which the ozone concentration measurementsare made and from which conduit withdrawal of the water having thepredetermined concentration of ozone can be done.
 11. A method accordingto claim 9 or 10, characterized by the water used being used accordingto the method being filtered and de-mineralized such that the waterexhibits a conductivity preferably <80 μS/cm.
 12. A method according toclaim 11, characterized by the water used being used according to themethod being filtered and de-mineralized such that the water exhibits aquality called soft water, and the preferred pH-interval is 2-4 pHunits.
 13. A method for detection of bacteria or other living mattercomprising the step of supplying water, having dissolved ozone thereinof a known first concentration, said water prepared according to claim12, to an object, measuring the ozone concentration in said water assaid water is removed from the object to determine a secondconcentration, the difference between the first and second concentrationbeing a measure of the amount of bacteria or other living matter presenton or in said object.
 14. A subsystem for production of water havingozone dissolved therein, said system comprising: water feeding means(11, V1, 71, 30, 83) having means (V1) for controlling the flow of waterto the system and a filtering and de-mineralizing unit (30), a containermeans (60), ozone feeding means (10, 70, V2, F1, 20) having means (V2)for controlling the flow of the oxygen gas and/or air to the system, anozone generator, and means (V3) for distributing the flow of ozone gasto the mixing means (BK), or to an outlet for ozone gas (14), a pressuresensor (PR) and a flow sensor (F1), for feeding ozone to a mixing means(BK) having a chamber having a water inlet (1) for water from the lowerpart of said container (60), an ozone inlet (2) for ozone from saidozone feeding means, said ozone inlet (2) having a diffusor meanscomprising a porous member, a water outlet (3) for water havingdissolved ozone through an outlet conduit leading to the upper pan ofthe container (60), whereat there are control means for monitoring theaddition of ozone independence of the measured ozone concentration, fordissolving ozone in said water; said mixing means (BK) drawing waterfrom the lower part of the container (60) by way of a conduit (77) thatis adapted to return the water having ozone dissolved therein from saidmixing means (BK), to a point in the container (60) below the liquidlevel in said container (60), ozone measuring means (51) that isarranged in the outlet conduit (71) from the lower part of the container(60), hat pumping means (P2) are provided to withdraw said water fromthe bottom of the container (60) past the concentration measuring means(51) and in dependence of a control signal from the control unit (50)either return the water to a point below said predetermined liquid levelin the container (60) or to deliver said water through The outlet (84,P2, 84, V4, 12) for water having the predetermined concentration ofozone, for measuring the ozone concentration of said water in thecontainer (60), water pumping means (P1, P2) for circulating said waterfrom he lower par of the container (60) to the upper part of thecontainer (60) in dependence of a measured ozone concentration in saidwater and said ozone feeding means feeding ozone to said mixing means(BK) in dependence of a predetermined ozone concentration value, saidcontainer (60) having an outlet (84, P2, 84, V4, 12) for water havingthe predetermined concentration of ozone, said system adapted tomaintain a predetermined liquid level in said container, said systemalso comprising a control unit (50) for controlling the system independence of measured physical parameters in the system, in conjunctionwith a mixing means to be used preferably with active water having ozonedissolved therein, said water system characterized by a treatmentchamber (912; 1012) or detachable connections for connecting anapparatus or device to be treated with the ozone-water mixture, at leastone ozone sensor (910, 911; 1011), means for registering and control atleast of the ozone content of the ozone-water mixture after said mixturehas flown through said treatment chamber (912; 1012) or said apparatusor device to be treated.
 15. A subsystem according to claim 14,characterized in a second ozone sensor being present after the outletfrom the container of the system and before the treatment chamber (912;1012) or detachable connections for connecting an apparatus or device tobe treated with the ozone-water mixture, said sensor used forcorrelation of the ozone content of the ozone-water mixture before andafter the treatment chamber (912; 1012) or detachable connections forconnecting an apparatus or device.
 16. A method of using a subsystemaccording to claim 15, characterized in that the used ozone water iswater having ozone dissolved therein is produced by the following steps:feeding filtered and de-mineralized water to a container to apredetermined level; re-circulating the water from the bottom of saidcontainer through a conduit comprising pumping means and mixing means;dissolving ozone gas in said re-circulated water in said mixing meansunder controlled inlet flows; feeding said water having dissolved ozoneto said container, measuring the instant ozone concentration of saidwater having dissolved ozone; said water having dissolved ozonere-circulated through the mixing means under addition of further ozonein dependence of said measurement of the ozone concentration; said laststep repeated when the measured ozone concentration is below apredetermined value.
 17. A method according to claim 16, characterizedin that the ozone water production also comprising the step ofre-circulating the water having dissolved ozone through a separateconduit in which the ozone concentration measurements are made and fromwhich conduit withdrawal of the water having the predeterminedconcentration of ozone can be done.
 18. A method according to claims 16or 17, characterized in the water used for producing the ozone waterbeing used according to the method being filtered and de-mineralizedsuch that the water exhibits a conductivity <80 μS/cm.
 19. A methodaccording to claim 18, characterized in the water used for producing theozone water being used according to the method being filtered andde-mineralized such that the water exhibits a quality called soft water.